Self-tightening chuck.



F. W. KUPKE. SELF TIGHTENING CHUGKUI ABPLIOATION FILED JULY 16, 1910.

v '114 I Patented Nov 5, .1912.

' said'sleeve and the chuck body is lessened Tightening Chucks, of whichthe following UNITED STATES PATENT OFFICE.

FRIEDRICH W. KUPKE, OF GERA, GERMANY.

SELF-TIGHTENING CHUCK.

jaws ma be set by hand or drawn tight by.

the wor ing resistance andmay again be released -by hand. s 1 i Thenovel chuckcomp'rises a ball=bearing located between the tighteningsleeve and the chuck body whereby the friction between which friction iscaused by the working re sistance and opposes the self tightening ofthechuck. -m

The invention is illustrated in the accompanying drawing in which:

Figure 1 represents in sectional elevation a closed self-centering chuckwhich embodies in desirable form the present improvements. Fig. '2 showssame in bottom plan view partly broken away. Fig. 3 illustrates insectional elevation the open chuck and Fig. 4 is a bottom plan view ofFig. 3.

The chuck body A is cylindrically bored out and provided with aright-handed thread A in the narrow portion of the hon ing. A cap Gserves as a support for the jaws E and overlaps part of the chuck bodyin the manner of an overlapping nut. The cap G forms inside a threadedbolt F which "fits axially into the chuck body and may be screwed in thethreaded portion of same.

Centrally a boring H is produced in the bolt F extending from its freeor outer end inwardly. The boring H permits of the introduction of toolsof various diameters. The jaws E which are supported by the cap G alsoreach into the boringH and may be radially moved therein by means ofslots provided in the bolt F. A nearly circular spring I has thetendency to force the jaws E apart against the wall of the tighteningsleeve D. The cap' G thus forms a holder for the jaws and may bedirectly screwed out of the chuck body A without allowing the singleelements to fall apart and every part of which may easily be reached.

According to the present invention a ball bearing is provided betweenthe chuck body and the'described arrangement for tighten ing the jaws E.The ball bearing consists of v Specification of Letters Patent.Application filed July 16, 1910. v Serial No. 572 ,284.

Patented Nov. 5, 1912.

a ring B having an annular groove in which the ballsC move, an-d thetightening sleeve D as shown inFigs. 1 and 3. Against the conical innersurface of the tightening sleeve D rest the jaws E with theircorrespohdiilgly shaped outer surfaces.

- .VVhen the capv G is screwed on, the jaws E al'e pressed by theconical inner surface of the tightening sleeve D toward the center andenter the axial boring H to grip there a the tool K in a self-centeringmanner. After this has been done, according to Fig.

3, the tightening sleeve D is pressed against the balls 0 of the ballbearing by the working resistance. The balls 0 of the ball hear ing thusprevent the friction on the chuck body A which otherwise is unavoidableand the self-tightening takes place. However it is also possible totighten by hand every tool or drill as much as the work requires. Thisrenders it possible to tighten securely only portions of short drillswithout risk of their being forced farther into the chuck by the workingpressure.

tool K only a slight tightening of theijaw holder F-G is-necessary forthe purpose.

of bringing the jaws E into contact with thetool shaft-l The workingresistance then further tightens thejaw holder in axial direction andthe jaws E firmly grip the tool shaft. The tightening may also be doneby hand in any desired manner. The release of the tool is effe ted inboth instances by hand without great exertion.

I claim as my invention 1. A self-tightening chuck, comprising a chuckbody cylindrica1ly bored out, a'ballbearing within, a tightenin sleeveresting against the ball bearing and liaving an inner conical and aouter. cylidrical surface, a cap on the chuck body, tightening jawssupported by said cap, and means for moving said jaws longitudinally,said sleeve being adapted to turn under the working resistance tocausesaid jaws to travel longitudinally with respect to said sleeve and saidchuck body tightening said jaws.

2. A self-tightening chuck, comprising a chuck body cylindrically boredout a ball bearing within, a tightening sleeve resting *having an innerchuck body and the against the sleeve,

on said cap cylindrically bored out and having slots through which thejaws reach and cooperating means on said shank and-said body to drawsaid-jaws over the conical face of the tightening sleeve to tighten thesame.

3. A self-tightening chuck for tools, comprising a chuck bodycylindricelly bored out, a ball bearing within, a tightening sleeveresting against the ball bearing and i conical and an outer cylindricalsurface, a capon the chuck body, loose tightening jaws supported by thecap, a nearly circular spring connecting said jaws and tending to forcethem apart against the wall of the sleeve, and an inner central shank onsaid cap cylindrioally bored out and having slots through which the jawsreach and cooperating means on said shank and said body to draw saidjaws over the conical face of the tightening sleeve tighten the same.

- 4. A self-tightening chuck for tools, com prising a chuck bodycylindrically bored out and having a right-handed thread in the narrowportion of the boring, a conical sleeve within, a ball bearing betweenthe conical sleeve, tightening jaws with conical outer surfaces restingand a can having a threaded shank to engage the thread on the chuckbody. I

5. A self-tightening chuck for tools, comprising a chuck bodycylindrically bored out and having a right-handed thread in the narrowportion of the boring, a conical tightening sleeve within, a ballbearing between the chuck body and the conical sleeve, conical jaws withouter conical surfaces restingagainstthe conical sleeve, and anoverlapping cap having a threaded shank cngaging the thread of the chuckoody and centrally bored out to receive a tool shaft.

6. A selfcentering chuck for tools, co1nprising a chuck body with acentral boring and narrow threaded inner portion, a tightening sleevewithin the chuck body, a ball bearing between the chuck body and thetightening sleeve,- tightening jaws within said sleeve, and a jawsupporting cup having a threaded shank centrally bored out and. providedwith slots through which the jaws reach.

Signed at Gera, Germany, of June, 1910.

Witnesses M. Goren,

CHARLFS NEUER.

this 10th day

